A common method of treating temporary or chronic pain is by application of heat to the afflicted area. Such heat treatments are used as a means of therapy for conditions which include aches, stiffness in muscles and joints, nerve pain, rheumatism and the like.
The human knee and elbow are two of the most vulnerable joints of the human body to overstress injury. While elastic compression bandages have been used to help stabilize knee movement during injury healing, heating pads, whirlpools, hot towels, and hydrocollators have been commonly used to apply heat to the knee to relieve the pain of knee injury. These pain relieving and stabilization devices, however, typically provide either one function or the other, but not both.
In general, the beneficial therapeutic effects from the administration of heat diminish after the heat source is removed. Therefore, depending on the temperature, it is desirable to provide a sustained heat source to the afflicted area for as long as possible to achieve the desired therapeutic benefits. Many of the current heating devices which require the thermal source to be replenished, such as the devices mentioned above or those employing reusable thermal packs containing water and/or microwaveable gels, are inconvenient to use on a regular and extended basis because the heat energy may not be immediately available when needed or released in a controllable manner.
Disposable heat packs based on iron oxidation, such as those described in U.S. Pat. Nos. 4,366,804, 4,649,895, 5,046,479 and Re.32,026, have been developed, however, such devices have proven not totally satisfactory. Many of these devices are bulky, cannot maintain a consistent and controlled temperature, and/or have unsatisfactory physical dimensions which hinder their effectiveness, and hence, deliver inconsistent, inconvenient and/or uncomfortable heat application to the body.
Proper positioning of the thermal energy also may not be maintainable during knee or elbow flexure with current heating devices. Elastic laminate structures have previously been used in a variety of products including elastic absorbent structures such as sweat bands, bandages, diapers, and incontinence devices. Several methods for producing these laminate structures, such as those disclosed in U.S. Pat. Nos. 4,522,863, 4,606,964, and 4,977,011, also currently exist. However, while these elastic laminate structures may be suitable for the purposes for which they were intended, they have strands which protrude on cut sides of the structure such that they can be a source of irritation when worn next to the body. Further, if an elastic laminate structure having a large modulus value (i. e., the ratio of stress to strain) is desired, elastic strands having a large cross-sectional area are generally required. Large strands of this type, however, can produce a rough or "nubby" feeling when placed in contact with the body.
The present inventors have developed disposable elastic thermal uniaxial joint wraps which maintain proper positioning during use on a user's knee or elbow while providing both compression and thermal energy in a controlled and sustainable manner. These wraps comprise one or more thermal bonded elastic laminate structures, which preferably comprise two carrier layers and an elastic member integrally thermal bonded therebetween, and one or more heat cells, preferably one or more thermal packs, wherein each thermal pack comprises a plurality of individual heat cells, which typically comprise an exothermic composition, preferably comprising a specific iron oxidation chemistry and specific physical dimensions and fill characteristics, spaced apart and fixedly attached across the thermal pack. The thermal bonded elastic laminate structures, when incorporated into the knee and/or elbow wraps of the present invention, substantially reduce delamination of the composite structure of the wraps during use, substantially reduce the rough and "nubby" feeling and irritation caused by strands protruding from cut edges, and provide the knee and/or elbow wraps with excellent conformity to the user's knee and/or elbow for uniform heat coverage and enhanced comfort.
It is therefore an object of the present invention to provide disposable elastic uniaxial joint wraps having excellent conformity to the user's knee and/or elbow for uniform heat coverage and enhanced comfort, which comprise one or more thermal bonded elastic laminate structures and one or more heat cells, which provide a controlled and sustained temperature and which reach their operating temperature range relatively quickly.
It is a further object of the present invention to provide disposable elastic uniaxial joint wraps, which comprise one or more thermal bonded elastic laminate structures, which comprise two carrier layers and an elastic member integrally bonded therebetween and one or more thermal packs comprising a plurality of individual heat cells. Such elastic laminate structures substantially reduce delamination of the composite structure of the wraps, substantially reduce the rough or "nubby" feeling and irritation caused by strands protruding from cut edges, and provide consistent, convenient, and comfortable heat application while deterring easy access to the heat cell contents.
It is a still further object of the present invention to provide disposable elastic uniaxial joint wraps, preferably for the knee and/or elbow, which comprise one or more thermal bonded elastic laminate structures, which preferably comprise two carrier layers and an elastic member integrally bonded therebetween, and one or more thermal packs having a unified structure of at least one continuous layer of semirigid material, which has different stiffness characteristics over a range of temperatures, and a plurality of individual heat cells, spaced apart and fixedly attached across the unified structure of the thermal pack providing good overall drapability while maintaining sufficient rigidity to maintain structural support of the heat cells and to prevent unacceptable stretching of the continuous layer or layers during processing or use.
These objectives and additional objectives will become readily apparent from the detailed description which follows.